Synthesis and Characterization of Analcime (ANA) Zeolite using a Kaolinitic Rock

Abstract

Analcime is nowadays an important component in dental porcelain sysytems, in heterogeneous catalysis, in the nanoelectronic field, in selective adsorption and in stomatology. Analcime synthesis from a kaolinite rock coming from Romana (Sassari, Italy) is here presented. A synthesis protocol is proposed that aims to make an improvement of synthesis conditions compared to the past. The hydrothermal treatment is in fact here achieved without aging times and without the use of sodium silicate, as reported in the literature. Lower calcination temperature, synthesis temperatures and crystallization times are verified in this work. The kaolin is subjected to calcination at the temperature of 650°C and then mixed with NaOH. The experiment is performed at ambient pressure and 170 ± 0.1°C. The degree of purity of Analcime is calculated in 97,57 % at 10h. Analcime is characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, inductively coupled plasma optical emission spectrometry and thermal analysis. Density is also calculated. Cell parameters and the amount of amorphous phase in the synthesis powders is estimated with quantitative phase analysis using the combined Rietveld and reference intensity ratio methods. The experimental conditions make the synthesis protocol particularly attractive from an economic point of view. Both chemical and physical characterization of Analcime is satisfactory making the experimental protocol very promising for an industrial transfer.